Hydroprocessing catalyst and method of making the same

ABSTRACT

The present invention is directed to a hydroprocessing catalyst containing at least one catalyst support, one or more metals, optionally one or more molecular sieves, optionally one or more promoters, wherein deposition of at least one of the metals is achieved in the presence of a modifying agent.

FIELD OF THE INVENTION

The present invention is directed to a catalyst for hydroprocessing acarbonaceous feedstock under hydroprocessing conditions, methods formaking the catalyst, and hydroprocessing processes using the catalyst ofthe present invention.

BACKGROUND OF THE INVENTION

Catalytic hydroprocessing refers to petroleum refining processes inwhich a carbonaceous feedstock is brought into contact with hydrogen anda catalyst, at a higher temperature and pressure, for the purpose ofremoving undesirable impurities and/or converting the feedstock to animproved product. Examples of hydroprocessing processes includehydrotreating, hydrodemetalization, hydrocracking and hydroisomerizationprocesses.

A hydroprocessing catalyst typically consists of one or more metalsdeposited on a support or carrier consisting of an amorphous oxideand/or a crystalline microporous material (e.g. a zeolite). Theselection of the support and metals depend upon the particularhydroprocessing process for which the catalyst is employed.

Petroleum refiners continue to seek out catalysts of improved activity,selectivity and/or stability. Increasing the activity of a catalystincreases the rate at which a chemical reaction proceeds under a givenset of conditions, increasing the selectivity of the catalysts decreasesunwanted by-products of the reaction, and increasing the stability of acatalyst increases its resistance to deactivation, that is, the usefullife of the catalyst is extended. In general, as the activity of thecatalyst is increased, the conditions required to produce a given endproduct, such as a hydrocarbon of a particular sulfur or nitrogencontent, becomes more mild (e.g. decreased temperature). Milderconditions require less energy to achieve a desired product, and thecatalyst's life is extended due to such factors as lower coke formationand the like.

It is well known in the art that modest or slight variations incompositional characteristics or methods of preparing hydroprocessingcatalysts have been known to have highly unpredictable activity,selectivity and/or stability effects on hydroprocessing reactions (suchas denitrogenation and/or desulfurization reactions). Accordingly,because of this unpredictability in the art, there continues to be newand surprising improvements in activity, selectivity and/or stability ofhydroprocessing catalysts.

SUMMARY OF THE INVENTION

The present invention is directed to a hydroprocessing catalystcontaining at least one catalyst support, one or more metals, optionallyone or more molecular sieves, and optionally one or more promoters,wherein deposition of at least one of the metals is achieved in thepresence of a modifying agent.

The present invention is also directed to methods for making thecatalyst, and hydroprocessing processes using the catalyst of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the polycyclic aromatics build up as a function oftime-on-stream for the catalyst compositions synthesized per theteachings of Examples 1 and 3 herein.

DETAILED DESCRIPTION OF THE INVENTION Introduction

The term “Periodic Table” refers to the version of IUPAC Periodic Tableof the Elements dated Jun. 22, 2007, and the numbering scheme for thePeriodic Table Groups is as described in Chemical and Engineering News,63(5), 27 (1985).

The term “bulk dry weight” to the weight of a material after calcinationat elevated temperature of over 1000° C. for 30 minutes.

The term “hydroprocessing” refers to a process in which a carbonaceousfeedstock is brought into contact with hydrogen and a catalyst, at ahigher temperature and pressure, for the purpose of removing undesirableimpurities and/or converting the feedstock to a desired product.

The term “hydrotreating” refers to a process that converts sulfur-and/or nitrogen-containing hydrocarbon feeds into hydrocarbon productswith reduced sulfur and/or nitrogen content, typically in conjunctionwith a hydrocracking function, and which generates hydrogen sulfideand/or ammonia (respectively) as byproducts.

The term “hydrocracking” refers to a process in which hydrogenation anddehydrogenation accompanies the cracking/fragmentation of hydrocarbons,e.g., converting heavier hydrocarbons into lighter hydrocarbons, orconverting aromatics and/or cycloparaffins (naphthenes) into non-cyclicbranched paraffins

The term “hydroisomerization” refers to a process in which normalparaffins are isomerized to their more branched counterparts in thepresence of hydrogen over a catalyst.

The term “hydrodemetalization” refers to a process that removesundesirable metals from hydrocarbon feeds into hydrocarbon products withreduced metal content.

The term “gas-to-liquid” (GTL) refers to a process in which gas-phasehydrocarbons such as natural gas are converted to longer-chainhydrocarbons such as diesel fuel via direct conversion or via syngas asan intermediate, for example using the Fischer-Tropsch process.

The term “framework topology” and its preceding three-letter frameworkcode refers to the Framework Type data provided for the framework codein “Atlas of Zeolite Types” 6^(th) Edition, 2007.

The term “alkenyl,” as used herein, represents a straight or branchedchain group of one to twelve carbon atoms derived from a straight orbranched chain hydrocarbon containing at least one carbon-carbon doublebond.

The term “hydroxyalkyl,” as used herein, represents one or more hydroxylgroups attached to the parent molecular moiety through an alkyl group.

The term “alkoxyalkyl,” as used herein, represents one or more alkoxygroups attached to the parent molecular moiety through an alkyl group.

The term “aminoalkyl,” as used herein, represents one or more aminogroups attached to the parent molecular moiety through an alkyl group.

The term “oxoalkyl,” as used herein, represents one or more ether groupsattached to the parent molecular moiety through an alkyl group.

The term “carboxyalkyl,” as used herein, represents one or more carboxylgroups attached to the parent molecular moiety through an alkyl group.

The term “aminocarboxyalkyl,” as used herein, represents one or morecarboxyl groups and one or more amino groups attached to the parentmolecular moiety through an alkyl group.

The term “hydroxycarboxyalkyl,” as used herein, represents one or morecarboxyl groups and one or more hydroxyl groups attached to the parentmolecular moiety through an alkyl group.

Where permitted, all publications, patents and patent applications citedin this application are herein incorporated by reference in theirentirety; to the extent such disclosure is not inconsistent with thepresent invention.

Unless otherwise specified, the recitation of a genus of elements,materials or other components, from which an individual component ormixture of components can be selected, is intended to include allpossible sub-generic combinations of the listed components and mixturesthereof. Also, “include” and its variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that may also be useful in the materials,compositions and methods of this invention.

Properties for the materials described herein are determined as follows:

(a) Constrained index (Cl): indicates the total cracking conversion of a50/50 mixture of n-hexane and 3-methyl-pentane by a sample catalyst at900° F. (482° C.), 0.68 WHSV. Samples are prepared according to themethod described in U.S. Pat. No. 7,063,828 to Zones and Burton, issuedJun. 20, 2006.

(b) Brønsted acidity: determined byisopropylamine-temperature-programmed desorption (IPam TPD) adapted fromthe published descriptions by T. J. Gricus Kofke, R. K. Gorte, W. E.Farneth, J. Catal. 114, 34-45, 1988; T. J. Gricus Kifke, R. J. Gorte, G.T. Kokotailo, J. Catal. 115, 265-272, 1989; J. G. Tittensor, R. J. Gorteand D. M. Chapman, J. Catal. 138, 714-720, 1992.

(c) SiO₂/Al₂O₃ Ratio (SAR): determined by ICP elemental analysis. A SARof infinity (∞) represents the case where there is no aluminum in thezeolite, i.e., the mole ratio of silica to alumina is infinity. In thatcase the molecular sieve is comprised of essentially all of silica.

(d) Surface area: determined by N₂ adsorption at its boilingtemperature. BET surface area is calculated by the 5-point method atP/P₀=0.050, 0.088, 0.125, 0.163, and 0.200. Samples are firstpre-treated at 400° C. for 6 hours in the presence of flowing, dry N₂ soas to eliminate any adsorbed volatiles like water or organics.

(e) Micropore volume: determined by N₂ adsorption at its boilingtemperature. Micropore volume is calculated by the t-plot method atP/P₀=0.050, 0.088, 0.125, 0.163, and 0.200. Samples are firstpre-treated at 400° C. for 6 hours in the presence of flowing, dry N₂ soas to eliminate any adsorbed volatiles like water or organics.

(f) Mesopore pore diameter: determined by N₂ adsorption at its boilingtemperature. Mesopore pore diameter is calculated from N₂ isotherms bythe BJH method described in E. P. Barrett, L. G. Joyner and P. P.Halenda, “The determination of pore volume and area distributions inporous substances. I. Computations from nitrogen isotherms.” J. Am.Chem. Soc. 73, 373-380, 1951. Samples are first pre-treated at 400° C.for 6 hours in the presence of flowing, dry N₂ so as to eliminate anyadsorbed volatiles like water or organics.

(g) Total pore volume: determined by N₂ adsorption at its boilingtemperature at P/P₀=0.990. Samples are first pre-treated at 400° C. for6 hours in the presence of flowing, dry N₂ so as to eliminate anyadsorbed volatiles like water or organics.

(h) Unit cell size: determined by X-ray powder diffraction.

(i) Alpha value: determined by an Alpha test adapted from the publisheddescriptions of the Mobil Alpha test (P. B. Weisz and J. N. Miale, J.Catal., 4, 527-529, 1965; J. N. Miale, N. Y. Chen, and P. B. Weisz, J.Catal., 6, 278-87, 1966). The “Alpha Value” is calculated as thecracking rate of the sample in question divided by the cracking rate ofa standard silica alumina sample. The resulting “Alpha” is a measure ofacid cracking activity which generally correlates with number of acidsites.

Hydroprocessing Catalyst Composition

The present invention is directed to a hydroprocessing catalystcontaining at least one catalyst support, one or more metals, optionallyone or more molecular sieves, and optionally one or more promoters,wherein deposition of at least one of the metals is achieved in thepresence of a modifying agent.

For each embodiment described herein, the catalyst support is selectedfrom the group consisting of alumina, silica, zirconia, titanium oxide,magnesium oxide, thorium oxide, beryllium oxide, alumina-silica,alumina-titanium oxide, alumina-magnesium oxide, silica-magnesium oxide,silica-zirconia, silica-thorium oxide, silica-beryllium oxide,silica-titanium oxide, titanium oxide-zirconia, silica-alumina-zirconia,silica-alumina-thorium oxide, silica-alumina-titanium oxide orsilica-alumina-magnesium oxide, preferably alumina, silica-alumina, andcombinations thereof.

In one subembodiment, the catalyst support is an alumina selected fromthe group consisting of γ-alumina, η-alumina, θ-alumina, δ-alumina,χ-alumina, and mixtures thereof.

In another subembodiment, the catalyst support is an amorphoussilica-alumina material in which the mean mesopore diameter is between70 Å and 130 Å.

In another subembodiment, the catalyst support is an amorphoussilica-alumina material containing SiO₂ in an amount of 10 to 70 wt. %of the bulk dry weight of the carrier as determined by ICP elementalanalysis, a BET surface area of between 450 and 550 m²/g and a totalpore volume of between 0.75 and 1.05 mL/g.

In another subembodiment, the catalyst support is an amorphoussilica-alumina material containing SiO₂ in an amount of 10 to 70 wt. %of the bulk dry weight of the carrier as determined by ICP elementalanalysis, a BET surface area of between 450 and 550 m²/g, a total porevolume of between 0.75 and 1.05 mL/g, and a mean mesopore diameter isbetween 70 Å and 130 Å.

In another subembodiment, the catalyst support is a highly homogeneousamorphous silica -alumina material having a surface to bulk silica toalumina ratio (S/B ratio) of 0.7 to 1.3, and a crystalline alumina phasepresent in an amount no more than about 10 wt. %.

${S\text{/}B\mspace{14mu} {Ratio}} = \frac{\left( {{Si}\text{/}{Al}\mspace{14mu} {atomic}\mspace{14mu} {ratio}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {surface}\mspace{14mu} {measured}\mspace{14mu} {by}\mspace{14mu} {XPS}} \right)}{\begin{pmatrix}{{Si}\text{/}{Al}\mspace{14mu} {atomic}\mspace{14mu} {ratio}\mspace{14mu} {of}\mspace{14mu} {the}} \\{{bulk}\mspace{14mu} {measured}\mspace{14mu} {by}\mspace{14mu} {elemental}\mspace{14mu} {analysis}}\end{pmatrix}}$

To determine the S/B ratio, the Si/Al atomic ratio of the silica-aluminasurface is measured using x-ray photoelectron spectroscopy (XPS). XPS isalso known as electron spectroscopy for chemical analysis (ESCA). Sincethe penetration depth of XPS is less than 50 Å, the Si/Al atomic ratiomeasured by XPS is for the surface chemical composition.

Use of XPS for silica-alumina characterization was published by W.Daneiell et al. in Applied Catalysis A, 196, 247-260, 2000. The XPStechnique is, therefore, effective in measuring the chemical compositionof the outer layer of catalytic particle surface. Other surfacemeasurement techniques, such as Auger electron spectroscopy (AES) andSecondary-ion mass spectroscopy (SIMS), could also be used formeasurement of the surface composition.

Separately, the bulk Si/Al ratio of the composition is determined fromICP elemental analysis. Then, by comparing the surface Si/Al ratio tothe bulk Si/Al ratio, the S/B ratio and the homogeneity ofsilica-alumina are determined. How the SB ratio defines the homogeneityof a particle is explained as follows. An S/B ratio of 1.0 means thematerial is completely homogeneous throughout the particles. An S/Bratio of less than 1.0 means the particle surface is enriched withaluminum (or depleted with silicon), and aluminum is predominantlylocated on the external surface of the particles. The S/B ratio of morethan 1.0 means the particle surface is enriched with silicon (ordepleted with aluminum), and aluminum is predominantly located on theinternal area of the particles.

For each embodiment described herein, the amount of catalyst support inthe hydroprocessing catalyst is from 5 wt. % to 80 wt. % based on thebulk dry weight of the hydroprocessing catalyst.

For each embodiment described herein, the hydroprocessing catalyst mayoptionally contain one or more molecular sieves selected from the groupconsisting of BEA-, ISV-, BEC-, IWR-, MTW-, *STO-, OFF-, MAZ-, MOR-,MOZ-, AFI-, *NRE-, SSY-, FAU-, EMT-, ITQ-21-, ERT-, ITQ-33-, andITQ-37-type molecular sieves, and mixtures thereof.

In one subembodiment, the one or more molecular sieves selected from thegroup consisting of molecular sieves having a FAU framework topology,molecular sieves having a BEA framework topology, and mixtures thereof.

The amount of molecular sieve material in the hydroprocessing catalystis from 0 wt. % to 60 wt. % based on the bulk dry weight of thehydroprocessing catalyst. In one subembodiment, the amount of molecularsieve material in the hydroprocessing catalyst is from 0.5 wt. % to 40%wt. %.

In one subembodiment, the molecular sieve is a Y zeolite with a unitcell size of 24.15 Å-24.45 Å. In another subembodiment, the molecularsieve is a Y zeolite with a unit cell size of 24.15 Å-24.35 Å. Inanother subembodiment, the molecular sieve is a low-acidity, highlydealuminated ultrastable Y zeolite having an Alpha value of less than 5and a Brønsted acidity of from 1 to 40. In one subembodiment, themolecular sieve is a Y zeolite having the properties described in Table1 below.

TABLE 1 Alpha value 0.01-5 CI 0.05-5% Brønsted acidity 1-40 μmole/g SAR80-150 surface area 650-750 m²/g micropore volume 0.25-0.30 mL/g totalpore volume 0.51-0.55 mL/g unit cell size 24.15-24.35 Å

In another subembodiment, the molecular sieve is a Y zeolite having theproperties described in Table 2 below.

TABLE 2 SAR 10-∞ micropore volume 0.15-0.27 mL/g BET surface area700-825 m²/g unit cell size 24.15-24.45 Å

In another subembodiment, the catalyst contains from 0.1 wt. % to 40 wt.% (based on the bulk dry weight of the catalyst) of a Y zeolite havingthe properties described Table 2 above, and from 1 wt. % to 60 wt. %(based on the bulk dry weight of the catalyst) of a low-acidity, highlydealuminated ultrastable Y zeolite having an Alpha value of less thanabout 5 and Brønsted acidity of from 1 to 40 micro-mole/g.

As described herein above, the hydroprocessing catalyst of the presentinvention contains one or more metals. For each embodiment describedherein, each metal employed is selected from the group consisting ofelements from Group 6 and Groups 8 through 10 of the Periodic Table, andmixtures thereof. In one subembodiment, each metal is selected from thegroup consisting of nickel (Ni), palladium (Pd), platinum (Pt), cobalt(Co), iron (Fe), chromium (Cr), molybdenum (Mo), tungsten (W), andmixtures thereof. In another subembodiment, the hydroprocessing catalystcontains at least one Group 6 metal and at least one metal selected fromGroups 8 through 10 of the periodic table. Exemplary metal combinationsinclude Ni/Mo/W, Ni/Mo, Ni/W, Co/Mo, Co/W, Co/W/Mo and Ni/Co/W/Mo.

The total amount of metal oxide material in the hydroprocessing catalystis from 0.1 wt. % to 90 wt. % based on the bulk dry weight of thehydroprocessing catalyst. In one subembodiment, the hydroprocessingcatalyst contains from 2 wt. % to 10 wt. % of nickel oxide and from 8wt. % to 40 wt. % of tungsten oxide based on the bulk dry weight of thehydroprocessing catalyst.

A diluent may be employed in the formation of the hydroprocessingcatalyst. Suitable diluents include inorganic oxides such as aluminumoxide and silicon oxide, titanium oxide, clays, ceria, and zirconia, andmixture of thereof. The amount of diluent in the hydroprocessingcatalyst is from 0 wt. % to 35 wt. % based on the bulk dry weight of thehydroprocessing catalyst. In one subembodiment, the amount of diluent inthe hydroprocessing catalyst is from 0.1 wt. % to 25 wt. % based on thebulk dry weight of the hydroprocessing catalyst.

The hydroprocessing catalyst of the present invention may contain one ormore promoters selected from the group consisting of phosphorous (P),boron (B), fluorine (F), silicon (Si), aluminum (Al), zinc (Zn),manganese (Mn), and mixtures thereof. The amount of promoter in thehydroprocessing catalyst is from 0 wt. % to 10 wt. % based on the bulkdry weight of the hydroprocessing catalyst. In one subembodiment, theamount of promoter in the hydroprocessing catalyst is from 0.1 wt. % to5 wt. % based on the bulk dry weight of the hydroprocessing catalyst.

Preparation of the Hydroprocessing Catalyst

In the present invention, deposition of at least one of the metals onthe catalyst is achieved in the presence of a modifying agent. In oneembodiment, a shaped hydroprocessing catalyst is prepared by:

(a) forming an extrudable mass containing at least the amorphoussilica-alumina catalyst support,

(b) extruding then calcining the mass to form a calcined extrudate,

(c) exposing the calcined extrudate to an impregnation solutioncontaining at least one metal and a modifying agent to form animpregnated extrudate, and

(d) drying the impregnated extrudate at a temperature below thedecomposition temperature of the modifying agent and sufficient toremove the impregnation solution solvent, to form a dried impregnatedextrudate.

The diluent, promoter and/or molecular sieve (if employed) may becombined with the carrier when forming the extrudable mass. In anotherembodiment, the carrier and (optionally) the diluent, promoter and/ormolecular sieve can be impregnated before or after being formed into thedesired shapes.

In one embodiment, deposition of at least one of the metals is achievedin the presence of a modifying agent is selected from the groupconsisting of compounds represented by structures (1) through (4),including condensated forms thereof:

wherein:

(1) R₁, R₂ and R₃ are independently selected from the group consistingof hydrogen; hydroxyl; methyl; amine; and linear or branched,substituted or unsubstituted C₁-C₃ alkyl groups, C₁-C₃ alkenyl groups,C₁-C₃ hydroxyalkyl groups, C₁-C₃ alkoxyalkyl groups, C₁-C₃ aminoalkylgroups, C₁-C₃ oxoalkyl groups, C₁-C₃ carboxyalkyl groups, C₁-C₃aminocarboxyalkyl groups and C₁-C₃ hydroxycarboxyalkyl groups;

(2) R₄ through R₁₀ are independently selected from the group consistingof hydrogen; hydroxyl; and linear or branched, substituted orunsubstituted C₂-C₃ carboxyalkyl groups; and

(3) R₁₁ is selected from the group consisting of linear or branched,saturated and unsaturated, substituted or unsubstituted C₁-C₃ alkylgroups, C₁-C₃ hydroxyalkyl groups, and C₁-C₃ oxoalkyl groups.

Representative examples of modifying agents useful in this embodimentinclude 2,3-dihydroxy-succinic acid, ethanedioic acid, 2-hydroxyaceticacid, 2-hydroxy-propanoic acid, 2-hydroxy-1,2,3-propanetricarboxylicacid, methoxyacetic acid, cis-1,2-ethylene dicarboxylic acid,hydroethane-1,2-dicarboxyic acid, ethane-1,2-diol, propane-1,2,3-triol,propanedioic acid, and α-hydro-ω-hydroxypoly(oxyethylene).

In an alternate embodiment, deposition of at least one of the metals isachieved in the presence of a modifying agent selected from the groupconsisting of N,N′-bis(2-aminoethyl)-1,2-ethane-diamine,2-amino-3-(1H-indol-3-yl)-propanoic acid, benzaldehyde,[[(carboxymethyl)imino]bis(ethylenenitrilo)]-tetra-acetic acid,1,2-cyclohexanediamine, 2-hydroxybenzoic acid, thiocyanate, thiosulfate,thiourea, pyridine, and quinoline.

The modifying agent impedes metal aggregation, thereby enhancing theactivity and selectivity of the catalyst.

For each embodiment described herein, the amount of modifying agent inthe pre-calcined hydroprocessing catalyst is from 2 wt. % to 18 wt. %based on the bulk dry weight of the hydroprocessing catalyst.

The calcination of the extruded mass will vary depending on theparticular support selected. Typically, the extruded mass can becalcined at a temperature between 752° F. (400° C.) and 1200° F. (650°C.) for a period of between 1 and 3 hours.

Non-limiting examples of suitable solvents include water and C₁ to C₃alcohols. Other suitable solvents can include polar solvents such asalcohols, ethers, and amines. Water is a preferred solvent. It is alsopreferred that the metal compounds be water soluble and that a solutionof each be formed, or a single solution containing both metals beformed. The modifying agent can be prepared in a suitable solvent,preferably water. The three solvent components can be mixed in anysequence. That is, all three can be blended together at the same time,or they can be sequentially mixed in any order. In an embodiment, it ispreferred to first mix the one or more metal components in an aqueousmedia, than add the modifying agent.

The amount of metal precursors and modifying agent in the impregnationsolution should be selected to achieve preferred ratios of metal tomodifying agent in the catalyst precursor after drying.

The calcined extrudate is exposed to the impregnation solution untilincipient wetness is achieved, typically for a period of between 1 and100 hours (more typically between 1 and 5 hours) at room temperature to212° F. (100° C.) while tumbling the extrudates, following by aging forfrom 0.1 to 10 hours, typically from about 0.5 to about 5 hours.

The drying step is conducted at a temperature sufficient to remove theimpregnation solution solvent, but below the decomposition temperatureof the modifying agent. In another embodiment, the dried impregnatedextrudate is then calcined at a temperature above the decompositiontemperature of the modifying agent, typically from about 500° F. (260°C.) to 1100° F. (590° C.), for an effective amount of time, to convertthe metals to metal oxides. The present invention contemplates that whenthe impregnated extrudate is to be calcined, it will undergo dryingduring the period where the temperature is being elevated or ramped tothe intended calcination temperature. This effective amount of time willrange from about 0.5 to about 24 hours, typically from about 1 to about5 hours. The calcination can be carried out in the presence of a flowingoxygen-containing gas such as air, a flowing inert gas such as nitrogen,or a combination of oxygen-containing and inert gases.

The dried and calcined hydroprocessing catalysts of the presentinvention can be sulfided to form an active catalyst. Sulfiding of thecatalyst precursor to form the catalyst can be performed prior tointroduction of the catalyst into a reactor (thus ex-situ presulfiding),or can be carried out in the reactor (in-situ sulfiding).

Suitable sulfiding agents include elemental sulfur, ammonium sulfide,ammonium polysulfide ([(NH₄)₂S_(x)), ammonium thiosulfate ((NH₄)₂S₂O₃),sodium thiosulfate (Na₂S₂O₃), thiourea CSN₂H₄, carbon disulfide,dimethyl disulfide (DMDS), dimethyl sulfide (DMS), dibutyl polysulfide(DBPS), mercaptanes, tertiarybutyl polysulfide (PSTB), tertiarynonylpolysulfide (PSTN), aqueous ammonium sulfide.

Generally, the sulfiding agent is present in an amount in excess of thestoichiometric amount required to form the sulfided catalyst. In anotherembodiment, the amount of sulfiding agent represents a sulphur to metalmole ratio of at least 3 to 1 to produce a sulfided catalyst.

The catalyst is converted into an active sulfided catalyst upon contactwith the sulfiding agent at a temperature of 150° F. to 900° F. (66° C.to 482° C.), from 10 minutes to 15 days, and under a H₂-containing gaspressure of 101 kPa to 25,000 kPa. If the sulfidation temperature isbelow the boiling point of the sulfiding agent, the process is generallycarried out at atmospheric pressure. Above the boiling temperature ofthe sulfiding agent/optional components, the reaction is generallycarried out at an increased pressure. As used herein, completion of thesulfidation process means that at least 95% of stoichiometric sulfurquantity necessary to convert the metals into for example, Co₉S₈, MoS₂,WS₂, Ni₃S₂, etc., has been consumed.

In one embodiment, the sulfiding can be carried out to completion in thegaseous phase with hydrogen and a sulfur-containing compound which isdecomposable into H₂S. Examples include mercaptanes, CS₂, thiophenes,DMS, DMDS and suitable S-containing refinery outlet gasses. The gaseousmixture of H₂ and sulfur containing compound can be the same ordifferent in the steps. The sulfidation in the gaseous phase can be donein any suitable manner, including a fixed bed process and a moving bedprocess (in which the catalyst moves relative to the reactor, e.g.,ebullated process and rotary furnace).

The contacting between the catalyst precursor with hydrogen and asulfur-containing compound can be done in one step at a temperature of68° F. to 700° F. (20° C. to 371 ° C.) at a pressure of 101 kPa to25,000 kPa for a period of 1 to 100 hrs. Typically, sulfidation iscarried out over a period of time with the temperature being increasedor ramped in increments and held over a period of time until completion.

In another embodiment of sulfidation in the gaseous phase, thesulfidation is done in two or more steps, with the first step being at alower temperature than the subsequent step(s).

In one embodiment, the sulfidation is carried out in the liquid phase.At first, the catalyst precursor is brought in contact with an organicliquid in an amount in the range of 20% to 500% of the catalyst totalpore volume. The contacting with the organic liquid can be at atemperature ranging from ambient to 248° F. (120° C.). After theincorporation of an organic liquid, the catalyst precursor is broughtinto contact with hydrogen and a sulfur-containing compound.

In one embodiment, the organic liquid has a boiling range of 200° F. to1200° F. (93° C. to 649° C.). Exemplary organic liquids includepetroleum fractions such as heavy oils, lubricating oil fractions likemineral lube oil, atmospheric gas oils, vacuum gas oils, straight rungas oils, white spirit, middle distillates like diesel, jet fuel andheating oil, naphthas, and gasoline. In one embodiment, the organicliquid contains less than 10 wt. % sulfur, and preferably less than 5wt. %.

Hydroprocessing Processes and Feeds

The catalyst composition according to the invention can be used in thedry or calcined form, in virtually all hydroprocessing processes totreat a plurality of feeds under wide-ranging reaction conditions, e.g.,at temperatures in the range of 200° to 450° C., hydrogen pressures inthe range of 5 to 300 bar, and space velocities (LHSV) in the range of0.05 to 10 h⁻¹. The hydroprocessing catalyst composition of theinvention is particularly suitable for hydrotreating hydrocarbonfeedstocks such as middle distillates, kero, naphtha, vacuum gas oils,and heavy gas oils.

Using the catalyst of the present invention, heavy petroleum residualfeedstocks, cyclic stocks and other hydrocrackate charge stocks can behydrocracked using the process conditions and catalyst componentsdisclosed in U.S. Pat. No. 4,910,006 and U.S. Pat. No. 5,316,753.Typically, hydrocracking can be carried out using the catalyst of thepresent invention by contacting the feedstock with hydrogen and thecatalyst at a temperature in the range of 175-485° C., hydrogenpressures in the range of 5 to 300 bar, and LHSV in the range of 0.1-30h⁻¹.

During hydrotreatment, oxygen, sulfur and nitrogen present in thehydrocarbonaceous feed is reduced to low levels. Aromatics and olefins,if present in the feed, may also have their double bonds saturated. Insome cases, the hydrotreating catalyst and hydrotreating conditions areselected to minimize cracking reactions, which can reduce the yield ofthe most desulfided product (typically useful as a fuel).

Hydrotreating conditions typically include a reaction temperaturebetween 204-482° C., for example 315-454° C.; a pressure between3.5-34.6 Mpa, for example 7.0-20.8 MPa; a feed rate (LHSV) of 0.5 hr⁻¹to 20 hr⁻¹ (v/v); and overall hydrogen consumption of 300 to 2000 scfper barrel of liquid hydrocarbon feed (53.4-356 m³ H₂/m³ feed).

Hydroisomerization conditions are dependent in large measure on the feedused and upon the desired product. The hydrogen to feed ratio istypically between 0.089 to 5.34 SCM/liter (standard cubic meters/liter),for example between 0.178 to 3.56 SCM/liter. Generally, hydrogen will beseparated from the product and recycled to the reaction zone. Typicalfeedstocks include light gas oil, heavy gas oils and reduced crudesboiling above about 177° C.

Lube oil may be prepared using the catalyst. For example, a C₂₀₊ lubeoil may be made by hydroisomerizing the paraffin fraction of the feed.Alternatively, the lubricating oil may be made by hydrocracking in ahydrocracking zone a hydrocarbonaceous feedstock to obtain an effluentcomprising a hydrocracked oil, and catalytically dewaxing the effluentat a temperature of at least about 200° C. and at a pressure between0.103 and 20.7 Mpa gauge, in the presence of added hydrogen gas.

Using the catalyst of the present invention, a FT wax feed generatedfrom a GTL process can be hydrocracked to diesel and jet fuels using bycontacting the catalyst of the present invention by the process withhydrogen and the catalyst at a temperature in the range of 175-485° C.,hydrogen pressures in the range of 5 to 300 bar, and LHSV in the rangeof 0.1-30 h⁻¹.

The following examples will serve to illustrate, but not limit thisinvention.

Catalyst Preparations EXAMPLE 1 Catalyst A—Comparative HydrocrackingCatalyst

A comparative hydrocracking catalyst was prepared per the followingprocedure: 67 parts by weight silica-alumina powder (obtained fromSasol), 25 parts by weight pseudo boehmite alumina powder (obtained fromSasol), and 8 parts by weight of zeolite Y (from Tosoh) were mixed well.A diluted HNO₃ acid aqueous solution (1 wt. %) was added to the mixpowder to form an extrudable paste. The paste was extruded in 1/16″asymmetric quadrilobe shape, and dried at 250° F. (121° C.) overnight.The dried extrudates were calcined at 1100° F. (593° C.) for 1 hour withpurging excess dry air, and cooled down to room temperature.

Impregnation of Ni and W was done using a solution containing ammoniummetatungstate and nickel nitrate in concentrations equal to the targetmetal loadings of 4 wt. % NiO and 28 wt. % WO₃ based on the bulk dryweight of the finished catalyst. The total volume of the solutionmatched the 103% water pore volume of the base extrudate sample(incipient wetness method). The metal solution was added to the baseextrudates gradually while tumbling the extrudates. When the solutionaddition was completed, the soaked extrudates were aged for 2 hours.Then the extrudates were dried at 250° F. (121° C.) overnight. The driedextrudates were calcined at 842° F. (450° C.) for 1 hour with purgingexcess dry air, and cooled down to room temperature. This catalyst isnamed Catalyst A and its physical properties are summarized in Table 3.

EXAMPLE 2 Catalyst B—Modified Hydrocracking Catalyst

A modified Ni/W hydrocracking catalyst was prepared using extrudatesprepared with the same formulation as that for Catalyst A. Impregnationof Ni and W was done using a solution containing ammonium metatungstateand nickel nitrate in concentrations equal to the target metal loadingsof 4 wt. % NiO and 28 wt. % WO₃ based on the bulk dry weight of thefinished catalyst. 2-Hydroxy 1,2,3-propanetricarboxylic (used as amodifying agent), in an amount equal to 10 wt. % of the bulk dry weightof the finished catalyst, was added to the Ni/W solution. The solutionwas heated to above 120° F. (49° C.) to ensure a completed dissolved(clear) solution. The total volume of the metal solution matched the103% water pore volume of the base extrudates (incipient wetnessmethod). The metal solution was added to the base extrudates graduallywhile tumbling the extrudates. When the solution addition was completed,the soaked extrudates were aged for 2 hours. Then the extrudates weredried at 400° F. (205° C.) for 2 hour with purging excess dry air, andcooled down to room temperature.

EXAMPLE 3 Catalyst C—Modified Hydrocracking Catalyst

Catalyst C was prepared by further calcination of a sampling of CatalystB at 842° F. (450° C.) for 1 hour.

EXAMPLE 4 Catalyst D—Modified Hydrocracking Catalyst

Catalyst D was prepared per following procedure: 55 parts silica-aluminapowder, 25 parts pseudo boehmite alumina powder, and 20 parts of zeoliteY were mixed well. To the mix, a diluted HNO₃ acid (1 wt. %) solutionwas added to form an extrudable paste. The paste was extruded in 1/16″asymmetric quadrilobe, and dried at 250° F. (121° C.) overnight. Thedried extrudates were calcined at 1100° F. (593° C.) for 1 hour withpurging excess dry air, and cooled down to room temperature.

Impregnation of Ni and W was done using a solution containing ammoniummetatungstate and nickel nitrate in concentrations equal to the targetmetal loadings of 4 wt. % NiO and 28 wt. % WO₃ based on the bulk dryweight of the finished catalyst. 2-Hydroxy 1,2,3-propanetricarboxylic(used as a modifying agent), in an amount equal to 10 wt. % of the bulkdry weight of the finished catalyst, was added to the Ni/W solution. Thesolution was heated to above 120° F. (49° C.) to ensure a clearsolution. The total volume of the metal solution matched the 103% waterpore volume of the base extrudates (incipient wetness method). The metalsolution was added to the base extrudates gradually while tumbling theextrudates. When the solution addition was completed, the soakedextrudates were aged for 2 hours. Then the extrudates were dried at 400°F. (205° C.) for 2 hour with purging excess dry air, and cooled down toroom temperature.

EXAMPLE 5 Catalyst E—Modified Hydrocracking Catalyst

Catalyst E was prepared by further calcination of a sampling of CatalystD at 842° F. (450° C.) for 1 hour.

EXAMPLE 6 Catalyst F—Modified Hydrocracking Catalyst

Catalyst F was prepared per following procedure: 69 parts silica-aluminapowder and 31 parts pseudo boehmite alumina powder were mixed well. Tothe mix, a diluted HNO₃ acid (1 wt. %) solution was added to form anextrudable paste. The paste was extruded in 1/16″ asymmetric quadrilobe,and dried at 250° F. (121° C.) overnight. The dried extrudates werecalcined at 1100° F. (593° C.) for 1 hour with purging excess dry air,and cooled down to room temperature.

Impregnation of Ni and W was done using a solution containing ammoniummetatungstate and nickel nitrate in concentrations equal to the targetmetal loadings of 4 wt. % NiO and 28 wt. % WO₃ based on the bulk dryweight of the finished catalyst. 2-Hydroxy 1,2,3-propanetricarboxylic(used as a modifying agent), in an amount equal to 10 wt. % of the bulkdry weight of the finished catalyst, was added to the Ni/W solution. Thesolution was heated to above 120° F. (49° C.) to ensure a clearsolution. The total volume of the metal solution matched the 103% waterpore volume of the base extrudates (incipient wetness method). The metalsolution was added to the base extrudates gradually while tumbling theextrudates. When the solution addition was completed, the soakedextrudates were aged for 2 hours. Then the extrudates were dried at 400°F. (205° C.) for 2 hour with purging excess dry air, and cooled down toroom temperature.

EXAMPLE 7 Catalyst G—Modified Hydrocracking Catalyst

Catalyst G was prepared by further calcination of a sampling of CatalystF at 842° F. (450° C.) for 1 hour.

TABLE 3 CATALYST A B C D E F G Base Zeolite, wt. % 8 8 8 20 20 0 0Silica Alumina, wt. % 67 67 67 55 55 69 69 Alumina, wt. % 25 25 25 25 2531 31 Porosity by N₂ uptake Surface area, m²/g 413 413 413 451 451 398398 Mean mesopore diameter, Å 90 90 90 80 80 94 94 Total pore volume,cc/g 0.69 0.69 0.69 0.67 0.67 0.69 0.69 Cl test n-C₆ conversion, wt. %1.3 1.3 1.3 2.0 2.0 0.4 0.4 i-C₆ conversion % 7.0 7.0 7.0 8.5 8.5 3.63.6 Finished Catalysts Metal content, wt. % NiO, wt. % 4 4 4 4 WO₃, wt.% 28 28 28 28 Porosity by N₂ uptake Surface area, m²/g 231 243 314 235Mean mesopore diameter, Å 89 98 71 112 Micropore pore volume, cc/g0.0059 0.0096 — Total pore volume, cc/g 0.40 0.42 0.41 0.44

EXAMPLE 8 Hydrocracking Performance

A variety of feeds were used to evaluate the hydrocracking performancesof the catalysts. In each test, the catalyst was subjected to thefollowing process conditions for feed 1: 2300 PSIG total pressure (2100PSIA H₂ at the reactor inlet), 5000 SCFB H₂, 1.0 LHSV, 60 LV % per passconversion. For feed 2, the testing conditions were: 1000 psig totalpressure (900 psia H₂ at the reactor inlet), 5000 scfb H₂, 1.0 LHSV, 65LV % per pass conversion. Table 4 summarizes the physical properties oftwo feeds used in the tests. Feed 1 is a hydrotreated VGO comprisinghigh concentrations of polycyclic aromatics. Feed 2 is a FT waxgenerated from a GTL process.

TABLE 4 Feed 1 Feed 2 API Gravity 33.4 40.4 Sulfur, ppm wt. 14.3 <2Nitrogen, ppm wt. 0.5 7.9 Oxygen, wt. % 0 0.7 PCI 333 — ComponentsParaffins, LV % 25.5 100 Naphthenes, LV % 66.5 0 Aromatics, LV % 8.0 0ASTM D2887 SimDis, -° F. (° C.) 0.5 wt. %/5 wt. % 771/819 437/572(381/437) (225/300)  10 wt. %/30 wt. % 840/886 624/734 (449/474)(329/390)  50 wt. %/— 925/—  809/—  (496)/—   (432)/—    70 wt. %/90 wt.%  970/1045  898/1002 (521/563) (481/539)  95 wt. %/99.5 wt. % 1087/12131038/1094 (586/656) (559/590)

Tables 5 and 6 compare the hydrocracking performance over catalystsprepared with and without a modifying agent.

TABLE 5 Hydrocracking Performance with Feed 1 Catalyst Activity, ° F. (°C.) Catalyst A Catalyst C No Loss Yields, wt. % Base Base C₄- 4.7 4.0C₅ - 250° F. (121° C.) 19.0 17.7 C₅ - 250-550° F. (121-288° C.) 54.053.4 C₅ - 550-700° F. (288-371° C.) 23.7 26.1

TABLE 6 Hydrocracking Performance with Feed 2 Catalyst Activity,Catalyst B Catalyst B* Catalyst D ° F. (° C.) Base Base Base No LossYields, Catalyst A +1° F. −13° F. −16° F. wt. % Base (+0.55° C.) (−7.2°C.) (−8.9° C.) C₄- 1.8 1.5 1.5 1.3 C₅-290° F. 15.4 12.7 13.4 13.4 (143°C.) C₅-290-700° F. 82.9 85.8 85.1 85.1 (143-371° C.) *with NH₃ scrubbing

Catalyst C shows superior HCR performance over Catalyst A. Catalyst Cgave a diesel yield at least 2 wt % higher than base case in expensiveof low gas yield (C₄—) and naphtha yield (C₅-250° F./121° C.). CatalystC reduced the low gas yield from 4.7 to 4.0 wt % and naphtha yield from19.0 to 17.7 wt. % in comparison with A. Catalyst C made about 2.5 wt %more heavy diesel (550-700° F./288-371 ° C.) than Catalyst A with a verycomparable jet yield (250-550° F./121-288° C.). The use of2-hydroxyl-1,2,3-propanetricarboxylic does not affect the catalystactivity.

For Feed 2 (Table 6), both catalysts B and D showed higher diesel yieldsthan Catalyst A by at least 2 wt. % at the expensive of low gas andnaphtha, similar to the findings with the petroleum feeds. Also observedwas a significant improvement in catalyst activity for Catalyst B and Dby more than 10° F. (5.5° C.) as compared to comparative Catalyst A.

Further, the modifying agent enhanced catalytic hydrogenation activitywith respect to saturate polycyclic aromatics in the feed. FIG. 1 showsthe polycyclic aromatics concentration (measured by polycyclic aromaticsindex, PCl) in a recycle liquid (e.g. >700° F. (371° C.) fraction) forFeed 1 over Catalysts A and C. Their initial concentration in the feedis also given for comparison. For Catalyst A, FIG. 1 clearly shows thatpolycyclic aromatics build up in the recycle liquid linearly withtime-on-stream over Catalyst A. For Catalyst C, the PCI value in therecycle liquid was much lower than that in the feed and in the recycleliquid with Catalyst A. Also, the PCI value maintained at the same levelwith time on stream on Catalyst C. This provides direct evidence for theimproved hydrogenation activity by the use of modifying agent. It isbeneficial for catalyst lifetime as the polycyclic aromatics areconsidered as precursors of coke formation on catalyst surfaces blockingcatalytically active sites inaccessible to reactant molecules.

1. A method for hydroprocessing a carbonaceous feedstock, comprisingcontacting the carbonaceous feedstock with a sulfided hydroprocessingcatalyst and hydrogen under hydroprocesssing conditions, thehydroprocessing catalyst comprising at least one metal deposited on anamorphous silica-alumina catalyst support containing SiO₂ in an amountof 10 wt. % to 70 wt. % of the dry bulk weight of the carrier asdetermined by ICP elemental analysis, a BET surface area of between 450m²/g and 550 m²/g, a total pore volume of between 0.75 mL/g and 1.05mL/g, and a mean mesopore diameter of between 70 Å and 130 Å, whereindeposition of the metal is achieved in the presence of a modifyingagent.
 2. The method of claim 1, wherein the sulfided hydroprocessingcatalyst further comprises at least one molecular sieve.
 3. The methodof claim 2, wherein the molecular sieve is a Y zeolite with a unit cellsize of between 24.15 Å and 24.45 Å.
 4. The method of claim 2, whereinthe at least one molecular sieve is a Y zeolite having asilica-to-alumina ratio of greater than 10, a micropore volume of from0.15 mL/g to 0.27 mL/g, a BET surface area of from 700 m²/g to 825 m²/g,and a unit cell size of from 24.15 Å to 24.45 Å.
 5. The method of claim1, wherein the sulfided hydroprocessing catalyst further comprises a Yzeolite having a silica-to-alumina ratio of greater than 10, a microporevolume of from 0.15 mL/g to 0.27 mL/g, a BET surface area of from 700m²/g to 825 m²/g, and a unit cell size of from 24.15 Å to 24.35 Å, and alow-acidity, highly dealuminated ultrastable Y zeolite having an Alphavalue of less than about 5 and Brønsted acidity of from 1 to 40micro-mole/g.
 6. The method of claim 1, wherein the modifying agent isselected from the group consisting of compounds represented bystructures (1) through (4), and condensated forms thereof:

wherein: (1) R₁, R₂ and R₃ are independently selected from the groupconsisting of hydrogen; hydroxyl; methyl; amine; and linear or branched,substituted or unsubstituted C₁-C₃ alkyl groups, C₁-C₃ alkenyl groups,C₁-C₃ hydroxyalkyl groups, C₁-C₃ alkoxyalkyl groups, C₁-C₃ aminoalkylgroups, C₁-C₃ oxoalkyl groups, C₁-C₃ carboxyalkyl groups, C₁-C₃aminocarboxyalkyl groups and C₁-C₃ hydroxycarboxyalkyl groups; (2) R₄through R₁₀ are independently selected from the group consisting ofhydrogen; hydroxyl; and linear or branched, substituted or unsubstitutedC₂-C₃ carboxyalkyl groups; and (3) R₁₁ is selected from the groupconsisting of linear or branched, saturated and unsaturated, substitutedor unsubstituted C₁-C₃ alkyl groups, C₁-C₃ hydroxyalkyl groups, andC₁-C₃ oxoalkyl groups.
 7. The method of claim 1, wherein the modifyingagent selected from the group consisting ofN,N′-bis(2-aminoethyl)-1,2-ethane-diamine,2-amino-3-(1H-indol-3-yl)-propanoic acid, benzaldehyde,[[(carboxymethyl)imino]bis(ethylenenitrilo)]-tetra-acetic acid,1,2-cyclohexanediamine, 2-hydroxybenzoic acid, thiocyanate, thiosulfate,thiourea, pyridine, and quinoline.
 8. The method of claim 1, wherein theat least one metal is selected from the group consisting of elementsfrom Group 6 and Groups 8 through 10 of the Periodic Table.
 9. Themethod of claim 8, wherein the at least one metal is selected from thegroup consisting of nickel (Ni), palladium (Pd), platinum (Pt), cobalt(Co), iron (Fe), chromium (Cr), molybdenum (Mo), tungsten (W), andmixtures thereof.
 10. The method of claim 8, wherein the at least onemetal is at least one metal selected from Group 6 of the Periodic Tableand at least one metal selected from Groups 8 through 10 of the periodictable.
 11. The method of claim 1, wherein the hydroprocessing conditionscomprise a temperature in the range of 175-485° C., hydrogen pressuresin the range of 5 to 300 bar, and LHSV in the range of 0.1-30 h⁻¹. 12.The method of claim 11, wherein the carbonaceous feedstock is generatedfrom a gas-to-liquid process.
 13. The method of claim 1, wherein thehydroprocessing conditions comprise a reaction temperature between204-482° C., a pressure between 3.5-34.6 Mpa, a feed rate (LHSV) of 0.5hr⁻¹ to 20 hr⁻¹ (v/v), and an overall hydrogen consumption of 53.4 to356 m³ H₂ per m³ of liquid hydrocarbon feed.
 14. A hydroprocessingcatalyst comprising at least one metal deposited on an amorphoussilica-alumina catalyst support containing SiO₂ in an amount of 10 wt. %to 70 wt. % of the dry bulk weight of the carrier as determined by ICPelemental analysis, a BET surface area of between 450 m²/g and 550 m²/g,a total pore volume of between 0.75 mL/g and 1.05 mL/g, and a meanmesopore diameter of between 70 Å and 130 Å, the sulfidedhydroprocessing catalyst made by a method comprising the steps of: (a)forming an extrudable mass comprising the amorphous silica-aluminacatalyst support, (b) extruding then calcining the mass to form acalcined extrudate, (c) exposing the calcined extrudate to animpregnation solution comprising the at least one metal and a modifyingagent to form an impregnated extrudate, and (d) drying the impregnatedextrudate at a temperature below the decomposition temperature of themodifying agent and sufficient to remove the impregnation solutionsolvent, to form a dried impregnated extrudate.
 15. The hydroprocessingcatalyst of claim 14, further comprising the step of calcining the driedimpregnated extrudate at a temperature high enough to remove themodifying agent and impregnation solution solvent and to convert the atleast one metal to a metal oxide.
 16. The hydroprocessing catalyst ofclaim 14, wherein the extrudable mass further comprises at least onemolecular sieve.
 17. The hydroprocessing catalyst of claim 16, whereinthe molecular sieve is a Y zeolite with a unit cell size of between24.15 Å and 24.45 Å.
 18. The hydroprocessing catalyst of claim 16,wherein the at least one molecular sieve is a Y zeolite having asilica-to-alumina ratio of greater than 10, a micropore volume of from0.15 mL/g to 0.27 mL/g, a BET surface area of from 700 m²/g to 825 m²/g,and a unit cell size of from 24.15 Å to 24.45 Å.
 19. The hydroprocessingcatalyst of claim 14, wherein the extrudable mass further comprises a Yzeolite having a silica-to-alumina ratio of greater than 10, a microporevolume of from 0.15 mL/g to 0.27 mL/g, a BET surface area of from 700m²/g to 825 m²/g, and a unit cell size of from 24.15 Å to 24.35 Å, and alow-acidity, highly dealuminated ultrastable Y zeolite having an Alphavalue of less than about 5 and Brønsted acidity of from 1 to 40micro-mole/g.
 20. The hydroprocessing catalyst of claim 14, wherein themodifying agent is selected from the group consisting of compoundsrepresented by structures (1) through (4), an condensated forms thereof:

wherein: (1) R₁, R₂ and R₃ are independently selected from the groupconsisting of hydrogen; hydroxyl; methyl; amine; and linear or branched,substituted or unsubstituted C₁-C₃ alkyl groups, C₁-C₃ alkenyl groups,C₁-C₃ hydroxyalkyl groups, C₁-C₃ alkoxyalkyl groups, C₁-C₃ aminoalkylgroups, C₁-C₃ oxoalkyl groups, C₁-C₃ carboxyalkyl groups, C₁-C₃aminocarboxyalkyl groups and C₁-C₃ hydroxycarboxyalkyl groups; (2) R₄through R₁₀ are independently selected from the group consisting ofhydrogen; hydroxyl; and linear or branched, substituted or unsubstitutedC₂-C₃ carboxyalkyl groups; and (3) R₁₁ is selected from the groupconsisting of linear or branched, saturated and unsaturated, substitutedor unsubstituted C₁-C₃ alkyl groups, C₁-C₃ hydroxyalkyl groups, andC₁-C₃ oxoalkyl groups.